乳清干酪的研制

乳清是生产干酪的副产物,含有多种营养物质。由于乳清中乳清蛋白含量低,直接生产乳清干酪的产率较低。本文向乳清中添加部分大豆蛋白粉制备乳清干酪,通过正交试验优化乳清干酪的配方。结果表明,乳清干酪的最佳配方为大豆蛋白粉添加量0.5%,酸化pH值5.5,加热温度80℃,加热时间30min。     

乳饼加工中乳清水制备乳清蛋白粉的工艺研究

以乳饼加工副产物——乳清水为原料,首先通过单因素试验优化超滤截留、浓缩乳清水主要固形物成分的技术参数,然后采用响应面法优化乳清蛋白粉的喷雾干燥工艺。结果表明,优化后的超滤参数为超滤压力0.3 MPa、超滤温度55℃,乳清蛋白粉的最佳喷雾干燥工艺条件为进风温度166℃、物料温度16℃、泵速32%（550 mL/h）。在该条件下乳清蛋白粉的干物质含量95.83%、溶解度94.61 g/100 g、热稳定性1.62 g、乳化性69.46%。用获得的乳清蛋白粉应用于酸奶制作,得到的酸奶发酵性能较好,产品感观风味、组织状态良好,其pH值、酸度、黏度、持水率分别为4.28、103.1 °T、7 800 mPa·s、77.9%。     

液相色谱-质谱法测定保健食品乳清蛋白粉类中叶酸含量的前处理条件的优化

目的优化液相色谱质谱联用法测定保健食品乳清蛋白粉类中叶酸含量的前处理方法。方法样品经过前处理,以乙腈和0.1%甲酸溶液为流动相,梯度洗脱,经Agilent Eclipse XDB-phenyl柱分离,使用液质联用仪检测。对比各个前处理方法对实验结果的影响。结果高氯酸-碳酸钠法前处理后,能很好地净化乳清蛋白中的蛋白质,并对实验结果保持准确科学,方法的精密度相对标准偏差为4.5%,回收率为95.1%~103.6%,相对标准偏差为3.7%。结论采用高氯酸-碳酸钠法前处理方法能测定保健食品中乳清蛋白粉类叶酸的含量,操作简便、准确、重现性好,分离效果明显,保护实验仪器和降低耗材,确保实验结果的准确性。     

蛋白粉你吃对了吗？

面对琳琅满目的蛋白质粉,你是否已经被绕得云里雾里了？蛋白质粉,顾名思义,就是从含蛋白质食品提纯的蛋白质粉末。大豆分离蛋白粉、乳清蛋白粉、复合蛋白粉、分离乳清蛋白粉、纯乳清蛋白粉、浓缩植物蛋白粉、胶原蛋白……消费者很容易受到促销员的左右而购买。     

花生乳清液发酵制备维生素饮料的探讨

<正> 在水溶法提取花生蛋白和花生毛油的生产中,毛油经精制而成优质的食用植物油,蛋白质则可研制成蛋白饮料、蛋白粉、纤维化蛋白等食品。然而可溶性的乳清蛋白及其它可溶性营养成分基本上都溶解在乳清液中而不为人们所重视。实际上花生仁中所含有的各种营养成分乳清液中均含有,这就表明乳清液同样具有开发价值。如果这种乳清液     

陶瓷膜超滤技术浓缩乳清的工艺参数研究

采用孔径为20nm的无机陶瓷膜超滤干酪副产物乳清,浓缩乳清蛋白。通过对膜过滤压力、温度以及乳清pH三个因素进行单因素分析以及正交实验优化,得到最佳工艺条件:操作压力0.25MPa,温度51℃,pH6.1,此条件下超滤膜渗透通量达到169.37L/m2.h,乳清蛋白可浓缩至5.4%,经喷雾干燥制得WPC蛋白质含量为38.2%。     

功能性大豆低聚糖饮料的研制

大豆乳清中含有的低聚糖和乳清蛋白具有很好的营养和保健功能.本研究通过对大豆分离蛋白生产工艺进行适当的改进,确定两次提取蛋白的料液比分别为1:7.5和1:7.5,第一次得到的乳清中固形物的总含量为3.95%,低聚糖含量2.68%,蛋白质含量0.65%.利用这部分乳清制备饮料,并对饮料进行感官评价,确定制备饮料的配方为每100mL乳清中加入蔗糖10g,柠檬酸0.5g,或每100mL乳清中加入木糖醇8g,得到饮料的口感和风味都较好.     

碱性蛋白酶水解乳清蛋白工艺条件的研究

为了降低乳清蛋白粉(whey powder,WP)中主要过敏原——β-乳球蛋白的含量,采用碱性酶对乳清蛋白粉进行水解.结果表明:乳清蛋白粉经80℃、30min的预处理,水解度有较大的提高,其抗原含量明显降低.最佳酶解条件是:酶解温度60℃、pH 9.0、加酶量19 000 U/100mL、酶解时间4 h.制得的水解液的水解度达16.0%,抗原残留量为原料的5%.酶解产物中的多肽可作为后续功能性产品的原料.     

响应面法优化电渗析乳清脱盐技术参数

试验探讨了利用电渗析技术应用于乳清脱盐技术的具体参数,采用4因素5水平二次回归正交旋转组合试验设计研究了乳清液脱盐的最佳优化工艺条件。选择电渗析工作电流、进料量、进料流速及进料温度进行单因素试验,并验证回归模型的显著性。结果表明,乳清液脱盐的最佳工艺条件为电渗析工作电流为45A、进料量26%、进料流速112mL/min、进料温度36℃,将含盐量为9%的乳清液降低到2.5%,脱盐率达到72%。     

超滤法提取大豆低聚糖的研究

大豆低聚糖是一种功能性低聚糖 ,具有促进双歧杆菌增殖的作用。本文对采用超滤技术提取大豆乳清前处理液中的大豆低聚糖进行了研究 ,探讨了压力和温度对大豆乳清前处理液超滤特性的影响 ,确定了每种膜的最佳超滤压力和超滤温度 ,并在此条件下进行超滤状况和膜阻力变化的研究 ,同时根据所得成品的成分分析选出了大豆乳清最佳超滤用膜 ,最后通过比较几种不同的清洗方法的清洗效果 ,选出了合适的超滤膜清洗方法。     

大豆低聚糖提取中超滤膜的选择

研究了大豆低聚糖提取过程中大豆乳清的超滤情况,结果表明：大豆乳清在不同的超滤膜、不同的截留分子量、压力和温度条件下,超滤速度随时间的变化不同;在超滤组允许的范围内,较高的操作压力和温度对大豆乳清的超滤有利;在最优的工艺条件下ＸＨＰ０３是提取大豆低聚糖的最佳用膜。     

Charged Ultrafiltration Membranes Increase the Selectivity of Whey Protein Separations

ABSTRACT:  Ultrafiltration is widely used to concentrate proteins, but fractionation of one protein from another is much less common. This study examined the use of positively charged membranes to increase the selectivity of ultrafiltration and allow the fractionation of proteins from cheese whey. By adding a positive charge to ultrafiltration membranes, and adjusting the solution pH, it was possible to permeate proteins having little or no charge, such as glycomacropeptide, and retain proteins having a positive charge. Placing a charge on the membrane increased the selectivity by over 600% compared to using an uncharged membrane. The data were fit using the stagnant film model that relates the observed sieving coefficient to membrane parameters such as the flux, mass transfer coefficient, and membrane Peclet number. The model was a useful tool for data analysis and for the scale up of membrane separations for whey protein fractionation.     

Preparation and composition of chhana whey powders using membrane processing techniques

Chhana is a traditional Indian product used widely in the confectionery industry. It is produced from cow's milk by a combination of heat and acid coagulation. Chhana whey contains about 6% milk solids yet the vast majority is wasted which leads to pollution problems. This study describes the chemical composition and various options for utilisation of chhana whey using membrane processes. Chhana whey powder containing 956 g kg^?1 total solids, 750 g kg^?1 lactose, 21 g kg^?1 protein. 60 g kg^?1 fat, 65 g kg^?1 ash was produced following concentration of chhana whey by reverse osmosis. Chhana whey protein concentrate powders containing 270, 350, 400 and 580 g kg^?1 protein were produced following ultrafiltration or diafiltration of chhana whey.     

阴离子交换树脂分离酪蛋白糖巨肽工艺条件优化

采用离子交换树脂从乳清粉中分离酪蛋白糖巨肽(casein glycomacropeptide,CGMP),筛选适于分离CGMP的离子交换树脂并考察静态吸附过程中吸附pH值、吸附时间、缓冲液浓度等因素对CGMP分离效果的影响。乳清粉溶液在pH5.1时离心除杂后与201×4树脂混合,吸附条件为吸附pH3.9、吸附时间1h、缓冲液浓度0.02mol/L、洗脱液为0.5mol/L pH4.0的氯化钠溶液、洗脱时间4h;100g乳清粉利用此工艺条件可得1.45g唾液酸含量10.4%(以蛋白质计)的CGMP。该工艺方法分离过程简单、纯化效果好、唾液酸含量高,适用于工业化生产。     

Evaluation of commercially available, wide-pore ultrafiltration membranes for production of α-lactalbumin-enriched whey protein concentrate

Commercially available, wide-pore ultrafiltration membranes were evaluated for production of α-lactalbumin (α-LA)-enriched whey protein concentrate (WPC). In this study microfiltration was used to produce a prepurified feed that was devoid of casein fines, lipid materials, and aggregated proteins. This prepurified feed was subsequently subjected to a wide-pore ultrafiltration process that produced an α-LA-enriched fraction in the permeate. We evaluated the performance of 3 membrane types and a range of transmembrane pressures. We determined that the optimal process used a polyvinylidene fluoride membrane (molecular weight cut-off of 50 kDa) operated at transmembrane pressure (TMP) of 207 kPa. This membrane type and operating pressure resulted in α-LA purity of 0.63, α-LA:β-LG ratio of 1.41, α-LA yield of 21.27%, and overall flux of 49.46 L/m²·h. The manufacturing cost of the process for a hypothetical plant indicated that α-LA-enriched WPC 80 (i.e., with 80% protein) could be produced at $17.92/kg when the price of whey was considered as an input cost. This price came down to $16.46/kg when the price of whey was not considered as an input cost. The results of this study indicate that production of a commercially viable α-LA-enriched WPC is possible and the process developed can be used to meet worldwide demand for α-LA-enriched whey protein.     

微滤-超滤联用技术优化牛初乳乳清中IgG富集工艺

为了高效富集IgG的同时减轻牛初乳的浪费问题,提高产品价值,本文采用微滤-超滤联用技术对牛初乳乳清中IgG进行富集。首先探究了微滤技术在牛初乳乳清除菌中的应用,并对其操作工艺进行优化,其次,利用超滤技术对微滤除菌后的牛初乳乳清进行富集,在单因素实验基础上,采用响应面对超滤工艺进行优化,并对富集后的牛初乳乳清进行品质分析。结果表明:牛初乳乳清微滤除菌的最佳工艺参数为:微滤压力为0.2 MPa、温度为30 ℃,超滤富集的最佳工艺参数为:超滤压力为0.15 MPa、温度为35 ℃、浓缩倍数为6倍、稀释次数为4次,按此条件进行牛初乳乳清的微滤-超滤操作,此时的IgG浓缩率为58.19%,膜通量为204.46 L/m2·h。富集后的牛初乳乳清品质分析表明:IgG含量为22760 μg/mL,IgG活性为718.31 IU/L,蛋白质含量为7.86%,脂肪含量为0.035%,菌落总数为2.4 lg CFU/mL。本研究为牛初乳乳清中IgG的进一步开发与综合利用提供了一定的参考依据。     

蛋白含量对牦牛乳清蛋白浓缩物功能特性的影响

通过不同截留分子质量的再生纤维素膜过滤纯化牦牛原乳清液和牦牛甜乳清液,分别制取牦牛原乳清蛋白浓缩物（native whey protein concentrate,NWPC）和牦牛甜乳清蛋白浓缩物（sweet whey protein concentrate,SWPC）,研究蛋白含量不同的乳清蛋白浓缩物（whey protein concentrate,WPC）主要成分（乳糖含量、pH值和总蛋白质含量）和功能特性（溶解性、持水性、持油性、起泡性、乳化性及热稳定性）的特征。结果表明：10 000 Da再生纤维素膜透析得到的牦牛WPC中总蛋白含量达到80%以上,不含乳糖,功能特性（溶解性、持水性、持油性、起泡性、乳化性及热稳定性）均显著高于经3 500 Da卷式膜、5 000 Da再生纤维素膜透析得牦牛WPC,WPC蛋白含量越高,其功能特性越好;不同蛋白含量的牦牛SWPC起泡能力、泡沫稳定性、乳化活性和乳化稳定性均显著（P＜0.05）高于牦牛NWPC。牦牛乳WPC最不稳定温度为85 ℃,高于荷斯坦牛乳WPC的80 ℃,热处理会适当改善牦牛WPC的起泡性能、乳化性能和热稳定性。通过膜牦牛处理获取的高蛋白含量的WPC,功能特性较好,应用广泛,对解决牦牛乳清资源的利用问题、保护环境、提高企业的经济效益起到关键性作用。     

The Potential Source of B. licheniformis Contamination During Whey Protein Concentrate 80 Manufacture

The objective of this study was to determine the possible source of predominant Bacillus licheniformis contamination in a whey protein concentrate (WPC) 80 manufacturing plant. Traditionally, microbial contaminants of WPC were believed to grow on the membrane surfaces of the ultrafiltration plant as this represents the largest surface area in the plant. Changes from hot to cold ultrafiltration have reduced the growth potential for bacteria on the membrane surfaces. Our recent studies of WPCs have shown the predominant microflora B. licheniformis would not grow in the membrane plant because of the low temperature (10 °C) and must be growing elsewhere. Contamination of dairy products is mostly due to bacteria being released from biofilm in the processing plant rather from the farm itself. Three different reconstituted WPC media at 1%, 5%, and 20% were used for biofilm growth and our results showed that B. licheniformis formed the best biofilm at 1% (low solids). Further investigations were done using 3 different media; tryptic soy broth, 1% reconstituted WPC80, and 1% reconstituted WPC80 enriched with lactose and minerals to examine biofilm growth of B. licheniformis on stainless steel. Thirty‐three B. licheniformis isolates varied in their ability to form biofilm on stainless steel with stronger biofilm in the presence of minerals. The source of biofilms of thermo‐resistant bacteria such as B. licheniformis is believed to be before the ultrafiltration zone represented by the 1% WPC with lactose and minerals where the whey protein concentration is about 0.6%.     

Use of acid whey protein concentrate as an ingredient in nonfat cup set-style yogurt

Acid whey resulting from the production of soft cheeses is a disposal problem for the dairy industry. Few uses have been found for acid whey because of its high ash content, low pH, and high organic acid content. The objective of this study was to explore the potential of recovery of whey protein from cottage cheese acid whey for use in yogurt. Cottage cheese acid whey and Cheddar cheese whey were produced from standard cottage cheese and Cheddar cheese-making procedures, respectively. The whey was separated and pasteurized by high temperature, short time pasteurization and stored at 4°C. Food-grade ammonium hydroxide was used to neutralize the acid whey to a pH of 6.4. The whey was heated to 50°C and concentrated using ultrafiltration and diafiltration with 11 polyethersulfone cartridge membrane filters (10,000-kDa cutoff) to 25% total solids and 80% protein. Skim milk was concentrated to 6% total protein. Nonfat, unflavored set-style yogurts (6.0 ± 0.1% protein, 15 ± 1.0% solids) were made from skim milk with added acid whey protein concentrate, skim milk with added sweet whey protein concentrate, or skim milk concentrate. Yogurt mixes were standardized to lactose and fat of 6.50% and 0.10%, respectively. Yogurt was fermented at 43°C to pH 4.6 and stored at 4°C. The experiment was replicated in triplicate. Titratable acidity, pH, whey separation, color, and gel strength were measured weekly in yogurts through 8 wk. Trained panel profiling was conducted on 0, 14, 28, and 56 d. Fat-free yogurts produced with added neutralized fresh liquid acid whey protein concentrate had flavor attributes similar those with added fresh liquid sweet whey protein but had lower gel strength attributes, which translated to differences in trained panel texture attributes and lower consumer liking scores for fat-free yogurt made with added acid whey protein ingredient. Difference in pH was the main contributor to texture differences, as higher pH in acid whey protein yogurts changed gel structure formation and water-holding capacity of the yogurt gel. In a second part of the study, the yogurt mix was reformulated to address texture differences. The reformulated yogurt mix at 2% milkfat and using a lower level of sweet and acid whey ingredient performed at parity with control yogurts in consumer sensory trials. Fresh liquid acid whey protein concentrates from cottage cheese manufacture can be used as a liquid protein ingredient source for manufacture of yogurt in the same factory.     

超滤法浓缩乳清蛋白前处理研究

为了提高乳清在进行超滤的通透性,从而提高超滤的效率,对利用CaCl2絮凝沉淀乳清的工艺条件进行研究,通过单因素和正交试验优化,综合考虑蛋白含量、脂肪含量和透光率3个指标,确定最佳的絮凝工艺条件为pH7.5、1mol/L CaCl2溶液添加量12mL/L、在60℃水浴缓慢搅拌絮凝15min。在最佳絮凝工艺条件下进行验证,结果表明：经过预处理后的乳清蛋白损失率只有13.6%,脂肪去除率达到86%以上,透光率也有显著提高。